Currently it is known to deposit the spacer frame or the spacer profile on a glass sheet to then mate the assembly to a second glass sheet so as to constitute the insulated glazing unit. This operation can also be repeated for obtaining an insulating glazing unit consisting of three glass sheets and two spacer frames or profiles, as well as n sheets and n−1 spacer frames or profiles.
In order to better understand the configuration of the glass sheet, not so much in its possible individual use but especially in its use in combination with other components, in particular the spacer frame or profile for constituting the insulating glazing unit 1, some concepts related to the intermediate components, i.e., the glass sheets 2 and the spacer frame or profile 3, and the final product, i.e., the insulating glazing unit 1, are summarized hereinafter, with reference to the figures, assuming that the subsequent use of the insulating glazing unit is known, i.e., as a component of doors or windows or of curtain walls or of structural faces. For organizing the description, it is easier to begin from the final product, breaking it down into its components.
The insulating glazing unit 1, in its traditional version, consists of a composition of two or more glass sheets 2, which are separated by one or more spacer frames 3, which are generally metallic, hollow and finely perforated in the face that is directed inwardly, the spacer frames containing, in their hollow part, hygroscopic material 4, which can exchange its capacity to absorb humidity through such fine perforations, and being coated, on the side walls that are adjacent to the glass sheets 2, with a first sealant 6, which has a sealing function and, on the outer wall, with a second sealant 7, which provides a mechanical coupling with the glass sheets 2 and the chamber (or chambers) delimited by the glass sheets and by the frame (frames) being able to contain air or gas 8 or gas mixtures 8 that give the insulating glazing unit particular properties, for example thermally insulating and/or soundproofing properties.
The use of a spacer profile 3 has recently become widespread that has a substantially rectangular cross-section and is made of expanded synthetic material (by way of non-limiting example: silicone or EPDM), which incorporates in its mass the hygroscopic material 4 and is pre-spread with acrylic adhesive 5 protected by a removable film 5′, as a substitute for the thermoplastic sealant 6. This innovative profile has two advantages: the low coefficient of heat transmission by conduction and the bond with the glass sheet, which becomes instantaneous because it is due to the acrylic adhesive 5 and is not, as in the case of spacer frames 3 made of metallic material or plastics, only due to the traditional thermoplastic sealant 6, which is subject to flow until the second cold sealant described hereinafter catalyzes, or to the second hot sealant (which is called hot melt and is particularly known in combination with the profile made of synthetic material) which is subject to flow even when it has cooled.
The use of the spacer profile 3 described in the preceding paragraph, i.e., pre-spread with the acrylic adhesive 5, but further provided with a recess (or rather a receptacle) 6′ designed to subsequently accommodate the thermoplastic sealant 6, has become widespread even more recently. This product belongs to the so-called TriSeal™ technology and constitutes an important innovation with respect to the traditional dual seal technology referred to in the two preceding paragraphs in the two different embodiments. The product is, for example, particularly employed in structural faces, in which, since the external sealant does not have gas- and water vapor-tight properties because it is silicone-based, these properties must be provided by the thermoplastic sealant 6. The levels of sealing therefore become three as opposed to the traditional two. The first one is obtained by means of the acrylic adhesive 5 (which provides immediate and stable anchoring between the glass sheets 2 and the spacer profile 3, with the advantage that it is possible to support stably the insulating glazing unit by gripping with suckers just one of the two or more glass sheets); the second one (which was the first one in the traditional system) is provided by the butyl sealant 6 (with a sealing function against the passage of moisture and gas), i.e., by the thermoplastic sealant; the third one (which was the second one in the traditional system) is provided by the polysulfide or polyurethane or silicone sealant 7 (which has the function of a mechanical-elastic bond between the components of the insulating glazing unit 1, consisting of the glass sheets 2 and the spacer frame 3), i.e., by the elastomeric sealant.
Since the present invention is about the production of an insulating glazing unit with the TriSeal™ technology, the numbering of the components has been organized so that the corresponding sealants 5, 6, 7, which indeed constitute the triple seal, are numbered progressively.
The glass sheets 2 used in the composition of the insulating glazing unit 1 can have different configurations depending on the use of such unit; for example, the outer glass sheet (“outer” being understood with respect to the interior of the building) can be normal or reflective/selective (for limiting heat input during the summer months) or laminated/armored (for intrusion prevention/vandalism prevention functions) or laminated/tempered (for safety functions) or combined (for example reflective and laminated, for obtaining a combination of properties). The inner glass sheet (“inner” being understood with respect to the interior of the building) can be normal or of the low-emissivity type (in order to limit heat loss during the winter months) or laminated/tempered (for safety functions) or combined (for example, of the low-emissivity and laminated type for obtaining a combination of properties).
From the above summary, it is already evident that a manufacturing line, in order to provide the insulating glazing unit product 1, requires many processes in sequence and in particular comprises the process of applying the spacer frame or spacer profile 3.
The process steps for producing the insulating glazing unit 1, each requiring a corresponding and particular machine, typically and preferably with a vertical arrangement (actually slightly inclined with respect to the vertical plane) to be arranged in series with respect to the other complementary ones, are, by way of non-exhaustive example and not in their entirety necessary, the following:                edging on the peripheral face of the glass sheet in order to remove any coatings, so as to allow and maintain over time the bond of the sealants and, in the case of the subject of the present application, of the acrylic adhesive 5 and of the thermoplastic sealant 6 and elastomeric sealant 7.        beveling of the sharp edges of the glass sheet, both in order to eliminate the edge defects introduced with the cutting operation and therefore the consequent possibility of crack triggering and to reduce the risks of injury in subsequent handling both of the glass sheet and of the insulating glazing unit.        washing of the individual glass sheets, with alternation of inner glass/outer glass (the orientation being as defined earlier).        application of the spacer frame: the previously manufactured frame, filled with hygroscopic material 4 and covered on its lateral faces with the thermoplastic sealant 6 which has sealing functions, in machines which are external with respect to the production line of the insulating glazing unit 1, is applied on one of the glass sheets that constitute the insulating glazing unit 1 at an appropriately provided station of the line for production of the insulating glazing unit 1. As an alternative, a continuous strip of spacer profile 3 made of expanded synthetic material is unwound from a spool 9 and is applied on one of the two glass sheets 2 until it forms a closed frame, which is built directly in adhesion on the glass sheet by means of the acrylic adhesive 5, after removal of the protective film 5′, and on the same line for the production of the insulating glazing unit 1. As a further alternative, and this regards the present invention, a continuous strip of spacer profile 3 made of expanded synthetic material is unwound from a spool 9 and is applied so that the wall 3p adheres to the first one of the two glass sheets 2 until it forms a closed frame, which is built directly against the glass sheet by means of the acrylic adhesive 5, after removal of the protective film 5′ and extrusion of the butyl sealant 6.        mating and pressing of the glass sheet/frame(s) assembly.        filling with gas of the chamber(s) thus obtained, either already during the preceding mating and pressing step or after said step, resorting in this case to the provision of holes in the spacer frame 3 according to several known techniques for the introduction of the gas.        second sealing of the perimetric compartment delimited by the internal faces of the glass sheets 2 and by the outer wall of the spacer frame 3; combining all the possibilities that can be used in the various processes, it can be performed with two-part/single-part polysulfide, two-part/single-part polyurethane, two-part/single-part silicone, hot melt, reactive hot melt (all are cold sealants, except for the hot melts, as is evident from the name itself).        
The process steps listed above can be performed by a respective machine automatically or semiautomatically.
In particular, in the known dual seal technique, the deposition of the spacer profile 3 made of expanded synthetic material is performed manually (i.e., with the intervention of the operator) typically on a tilting table, which changes its arrangement from vertical when it receives the glass sheet from the line to horizontal when the operator deposits the profile. It can be performed automatically in a section of the vertical line for the production of the insulating glazing unit 1, and therefore with a vertical arrangement.
In the now currently available technique known as TriSeal™, the deposition of the spacer profile 3 made of expanded synthetic material is performed manually (i.e., with the intervention of the operator), typically on a tilting table, which changes its arrangement from vertical when it receives the glass sheet from the line to horizontal when the operator deposits the profile. It also can be performed automatically (i.e., without the intervention of the operator), typically and preferably in a section that has a vertical arrangement like the insulating glazing unit production line itself (without however excluding solutions that have a horizontal arrangement) after the application, which is again automatic, of the lateral beads of butyl sealant 6 on the recesses (receptacles) 6′ of the lateral faces 3p and 3s of the spacer profile 3, in a station 500 that is intermediate between the station 400 for unwinding the spool 9 and the station 200 for the application of the spacer profile 3 on the first glass sheet 2.
Prior art in the same field, regarding machines and methods for applying the spacer profile on a glass sheet is disclosed in the documents mentioned hereinafter:                WO 2005/078227 A1, teaches working on the spacer profile after the spacer profile 3 has been mated on both walls 3p, 3s to the glass sheets 2 and is retained effectively by them by means of the adhesive sealant 5.        EP 1 528 214 A1, corresponding to DE 103 50 312 A1 dated Oct. 28, 2003, and US 2005/0247392 A1, in the name of Lisec Peter, specifically related to the application of a thermoplastic sealant 6 on a spacer profile 3 made of expanded synthetic material, which however is expressly not provided with adhesive sealant 5.        WO 2005/078227 A1, corresponding to US2005/0167028 A1 dated Feb. 4, 2004, in the name of Reichert Gerhard, assigned to Edgetech specifically related to the application of a thermoplastic sealant 6 on the recesses (receptacles) 6′ of the spacer frame 3 made of expanded synthetic material already provided with adhesive sealant 5 protected by a film 5′ on part of its side walls.        IT-TV2008A000047 dated Apr. 4, 2008, of the same applicant For. El. BASE di Vianello Fortunato & C. s.n.c., with respect to which the present invention is an improvement.        
In summary, these documents respectively teach, all with reference to a spacer profile 3 made of expanded synthetic material, the following:                EP 1 528 214 A1, application of the thermoplastic sealant at a station that is intermediate between the unwinding reel of the spool and the machine for applying the spacer profile 3 on the first glass sheet 2;        WO 2005/078227 A1, application of the thermoplastic sealant at a station that is intermediate between the unwinding reel of the spool and the machine for applying the spacer profile 3 provided with acrylic adhesive 5 on the first glass sheet 2;        IT-TV2008A000047, application of the thermoplastic sealant 6 directly on the extrusion head after cutting into the spacer profile 3 in the portions that correspond to the corners or cusps of the frame.        
Also known are devices which extrude the thermoplastic sealant 6, on a spacer profile 3 that is already coated with acrylic adhesive 5 and is provided with a receptacle 6′, after the unwinding of the spool along the path of the spacer profile 3 in the application head but prior to arrival at the part of the application head on which the devices for incision of the portions designed for the corners or cusps of the spacer frame 3 and for final cutting are located. Devices are known that extrude the thermoplastic sealant 6 in the path of the mechanisms that produce the incisions.
It is noted that extrusion of the thermoplastic sealant 6 before the spacer profile reaches the machine for applying it on one of the two glass sheets belongs to the background art of GB 2 045 229, which is not commented here since it is redundant with respect to disclosures of the four mentioned documents.
Main problems, inherent to the known techniques described above are as follows:                several discontinuities of the butyl sealant, because the transitions that occur during the application of the spacer profile on the glass sheet (due to the previous incision of the inside curve of the profile at the regions that will become a corner or cusp and due to the rotation of the head at the corner or cusp) and the transitions or pauses that occur in the transfer of work from one insulating glazing panel to the next force transient conditions also on the process for extrusion of the butyl sealant 6;        criticality of these discontinuities, not only from an aesthetic point of view (which is nonetheless critical especially in the case of structural faces, in which the entire wall of the insulating glazing unit 1 remains visible) but most of all from the functional point of view, the butyl sealant 6 having to meet the requirements of tightness to gas and water vapor; although these are not true interruptions, these discontinuities nonetheless constitute irregularities that are aggravated during the pressing step, since the effect of spreading the butyl sealant on the lateral faces of the spacer profile depends on the uniformity or lack thereof of the thickness and/or shape thereof that was produced during the extrusion step;        even in cases in which the transitions are compensated by means of speed variations or accumulation of the spacer profile, the devices that perform them being located in the same application head, such speed variations and accumulations become excessive in quantity and complex to control, especially since they depend on the length of the sides that constitute the perimeter of the spacer frame 1 and of their succession.        